When I type find . -type d -name "foo" command I get Permission denied error messages. How do I exclude all “permission denied: messages from the find command under Linux or Unix like operating systems?

I have Red Hat Enterprise Linux 6.x server. How do I find out and groups network bandwidth usage by process under Linux operating systems? How do I find out what programs are using network bandwidth under Linux operating systems? How can I see bandwidth usage per PID, command, and user on a Linux operating systems?

I recently updated my Mozilla Firefox. Firefox now includes a built-in PDF viewer that allows me to see PDF files found on the web without a plugin. The built-in PDF viewer is enabled by default. However, I found that this pdf viewer is not working properly with various web-sites, and it works slowly. How do disable the built-in PDF viewer so that I can use the Adobe PDF viewer or other PDF viewer that is shipped with my operating systems?